This invention relates to an improved process for the manufacture of gum bases. Specifically, this invention is a process where certain dry powder ingredients normally used in gum base formulations are pre-blended with liquefiable materials (e.g. elastomer plasticizers or molten waxes or softeners) before blending the dry ingredients into the elastomer component of the gum base.
Typical gum bases, particularly bubble bases include an elastomer component (e.g. styrene-butadiene rubber, polyvinyl acetate, natural rubber, and the like), softeners (e.g. fats, oils or mono- or diglycerides), waxes, elastomer plasticizers (e.g. rosin esters or terpene resins) and up to 60 percent of dry ingredients.
Formulations for gum bases vary widely and are based in part on customer requirements and specifications. Thus, conventional gum base manufacture can be relatively costly for some bases, because the economies of scale of large production runs cannot be achieved with some bases, because their formulae differ one from the another. Typically, a gum base is made on a production line that includes one or more gum base mixers and ingredient addition equipment. Once one base is made, new ingredients must be preweighed and delivered to the gum base mixers for manufacture of a different base. Thus, if a particular base has a short production run, there are proportionately higher costs due to the preparation and delivery of ingredients, that cause manufacturing delays.
In terms of weight percentages, the predominant type of dry ingredient in gum base is filler (e.g. talc or calcium carbonate), although important other dry ingredients such as flavorants (e.g. cocoa powder) and colorants are commonly used. Dry ingredients used in gum bases are almost invariably very fine (typically in powder form) so as not to impart a grainy texture to the ultimate product.
Unfortunately, the fine powder consistency of typical dry ingredient used in chewing gums can result in manufacturing problems. Even when the most advanced equipment is employed, such dry ingredients can become airborne.
Airborne powder from one gum base product can contaminate other gum base products being produced in the same plant. For example, some gum base products using acidic ingredients should not be exposed to calcium carbonate-containing fillers. Airborne contamination also necessitates frequent plant cleaning.
Finally, conventional processes for gum base manufacture can involve many individual blending steps, in some cases up to 30 or more separate additions of ingredients, depending upon the ingredients and equipment.